Method and apparatus for channel estimation in wireless communication system
The present disclosure relates to a pre-5 th -Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4 th -Generation (4G) communication system such as Long Term Evolution (LTE). The present disclosure provides a channel estimation method and apparatus by a reception end. The reception device includes a receiver and a controller. The receiver receives a reference signal. The controller identifies a first set of channel values for resources allocated for reference signals. The controller performs interpolation on the first set of channel values so as to identify second set of channel values for remaining resources. The interpolation method is determined based on at least one of Doppler frequency of a channel and channel quality. The controller processes received signals using the first set of channel values and the second set of channel values.
1. A method for operating a reception device, the method comprising:
obtaining a basis expansion model (BEM) basis vector based on reference signals received from a transmission device;
obtaining at least one BEM coefficient corresponding to at least one non-zero entry of a channel impulse response (CIR) based on the BEM basis vector;
obtaining the CIR based on the at least one BEM coefficient and the BEM basis vector;
obtaining a channel frequency response (CFR) from the CIR; and
processing received signals using the CFR.
2. The method of claim 1 , further comprising:
obtaining a second set of channel values of the CIR by performing an interpolation on a first set of channel values of the CIR based on the at least one BEM coefficient and the BEM basis vector.
3. The method of claim 2 , further comprising:
determining the at least one non-zero entry of the CIR; and
estimating the at least one BEM coefficient corresponding to the at least one non-zero entry,
wherein the CIR comprises the first set of channel values and the second set of channel values.
4. The method of claim 3 , wherein the determining of the at least one non-zero entry comprises:
generating a correlation vector by applying a matched filter to a residual signal; and
determining at least one entry of the correlation vector in which an energy value of the at least one entry of the correlation vector is greater than a reference value,
wherein the residual signal comprises at least part of the reference signals.
5. The method of claim 3 , wherein the determining of the at least one non-zero entry comprises:
determining at least one block among blocks in which values of all entries are non-zero in the CIR,
wherein the estimating of the at least one BEM coefficient comprises: estimating the at least one BEM coefficient corresponding to entries included in the at least one block, and
wherein each of the blocks comprises one or more entries all values of which are zero or non-zero.
6. The method of claim 5 , wherein the determining of the at least one block comprises:
generating a correlation vector by applying a matched filter to a residual signal; and
determining at least one block of the correlation vector in which an energy value of the at least one block of the correlation vector is greater than a reference value,
wherein the residual signal comprises at least part of the reference signals.
7. The method of claim 1 , wherein the BEM basis vector comprises a Legendre polynomial basis.
8. The method of claim 2 , further comprising determining a number of basis for the BEM basis vector based on at least one of a Doppler frequency of a channel associated with the CIR and a channel quality for the channel.
9. The method of claim 1 , wherein the reference signals are transmitted through a plurality of antennas of the transmission device, further comprising:
determining an antenna set for performing linear interpolation among the plurality of antennas based on at least one of a Doppler frequency of a channel associated with the CIR and a channel quality for the channel; and
determining a second set of channel values of the CIR, using the reference signals, for each of the plurality of antennas including antennas included in the antenna set,
wherein the second set of channel values for the antennas included in the antenna set are determined from the reference signals and an interpolation signal obtained by performing linear interpolation between the reference signals.
10. The method of claim 9 , further comprising:
determining the at least one non-zero entry of the CIR including a first set of channel values; and
determining at least one value corresponding to the at least one non-zero entry,
wherein the CIR comprises the first set of channel values and the second set of channel values.
11. An apparatus of a reception device comprising:
a transceiver configured to receive reference signals from a transmission device;
at least one processor configured to:
obtain a basis expansion model (BEM) basis vector based on the reference signals, obtain at least one BEM coefficient corresponding to at least one non-zero entry of a channel impulse response (CIR) based on the BEM basis vector,
obtain the CIR based on the at least one BEM coefficient and the BEM basis vector,
obtain a channel frequency response (CFR) from the CIR, and
process received signals using the CFR.
12. The apparatus of claim 11 , wherein the at least one processor is further configured to:
obtain a second set of channel values of the CIR by performing an interpolation on a first set of channel values of the CIR based on the at least one BEM coefficient and the BEM basis vector.
13. The apparatus of claim 12 , wherein the at least one processor is further configured to:
determine the at least one non-zero entry of the CIR, and
estimate the at least one BEM coefficient corresponding to the at least one non-zero entry,
wherein the CIR comprises the first set of channel values and the second set of channel values.
14. The apparatus of claim 13 , wherein the at least one processor is further configured to:
generate a correlation vector by applying a matched filter to a residual signal, and
determine at least one entry of the correlation vector in which an energy value of the at least one entry of the correlation vector is greater than a reference value,
wherein the residual signal comprises at least part of the reference signals.
15. The apparatus of claim 13 , wherein the at least one processor is further configured to:
determine at least one block among blocks in which values of all entries are non-zero in the CIR, and
estimate the at least one BEM coefficient corresponding to entries included in the at least one block,
wherein each of the blocks comprises one or more entries all values of which are zero or non-zero.
16. The apparatus of claim 15 , wherein the at least one processor is further configured to:
generate a correlation vector by applying a matched filter to a residual signal; and
determine at least one block of the correlation vector in which an energy value of the at least one bloc of the correlation vector is greater than a reference value,
wherein the residual signal comprises at least part of the reference signals.
17. The apparatus of claim 11 , wherein the BEM basis vector comprises a Legendre polynomial basis.
18. The apparatus of claim 12 , wherein the at least one processor is further configured to determine a number of basis for the BEM basis vector based on at least one of a Doppler frequency of a channel associated with the CIR and a channel quality for the channel.
19. The apparatus of claim 11 , wherein the reference signals are transmitted through a plurality of antennas of the transmission device,
wherein the at least one processor is further configured to:
determine an antenna set for performing linear interpolation among the plurality of antennas based on at least one of a Doppler frequency of a channel associated with the CIR and a channel quality for the channel, and
determine a second set of channel values of the CIR, using the reference signals, for each of the plurality of antennas including antennas included in the antenna set, and
wherein the second set of channel values for the antennas included in the antenna set are determined from the reference signals and an interpolation signal obtained by performing linear interpolation between the reference signals.
20. The apparatus of claim 19 , wherein the at least one processor is further configured to:
determine the at least one non-zero entry of the CIR including a first set of channel values, and
determine at least one value corresponding to the at least one non-zero entry, and wherein the CIR comprises the first set of channel values and the second set of channel values.